nimbus-eth2/beacon_chain/consensus_object_pools/exit_pool.nim

141 lines
5.5 KiB
Nim

# beacon_chain
# Copyright (c) 2020-2021 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
{.push raises: [Defect].}
import
# Standard libraries
std/[deques, intsets, tables],
# Status libraries
chronicles,
# Internal
../spec/[crypto, datatypes, helpers],
"."/[blockchain_dag, block_quarantine],
../beacon_node_types
export beacon_node_types, intsets
logScope: topics = "exitpool"
const
ATTESTER_SLASHINGS_BOUND* = MAX_ATTESTER_SLASHINGS * 2
PROPOSER_SLASHINGS_BOUND* = MAX_PROPOSER_SLASHINGS * 2
VOLUNTARY_EXITS_BOUND* = MAX_VOLUNTARY_EXITS * 2
proc init*(
T: type ExitPool, dag: ChainDAGRef, quarantine: QuarantineRef): T =
## Initialize an ExitPool from the dag `headState`
T(
# Allow for filtering out some exit messages during block production
attester_slashings:
initDeque[AttesterSlashing](initialSize = ATTESTER_SLASHINGS_BOUND.int),
proposer_slashings:
initDeque[ProposerSlashing](initialSize = PROPOSER_SLASHINGS_BOUND.int),
voluntary_exits:
initDeque[SignedVoluntaryExit](initialSize = VOLUNTARY_EXITS_BOUND.int),
dag: dag,
quarantine: quarantine
)
func addExitMessage*(subpool: var auto, exitMessage, bound: auto) =
# Prefer newer to older exit messages
while subpool.lenu64 >= bound:
discard subpool.popFirst()
subpool.addLast(exitMessage)
doAssert subpool.lenu64 <= bound
iterator getValidatorIndices(attester_slashing: AttesterSlashing): uint64 =
# TODO rely on sortedness and do this sans memory allocations, but it's only
# when producing a beacon block, which is rare bottlenecked elsewhere.
let
attestation_1_indices =
attester_slashing.attestation_1.attesting_indices.asSeq
attestation_2_indices =
attester_slashing.attestation_2.attesting_indices.asSeq
attester_slashed_indices =
toIntSet(attestation_1_indices) * toIntSet(attestation_2_indices)
for validator_index in attester_slashed_indices:
yield validator_index.uint64
iterator getValidatorIndices(proposer_slashing: ProposerSlashing): uint64 =
yield proposer_slashing.signed_header_1.message.proposer_index
iterator getValidatorIndices(voluntary_exit: SignedVoluntaryExit): uint64 =
yield voluntary_exit.message.validator_index
# TODO stew/sequtils2
template allIt(s, pred: untyped): bool =
# https://github.com/nim-lang/Nim/blob/version-1-2/lib/pure/collections/sequtils.nim#L640-L662
# without the items(...)
var result = true
for it {.inject.} in s:
if not pred:
result = false
break
result
func getExitMessagesForBlock[T](
subpool: var Deque[T], pool: var ExitPool, bound: uint64): seq[T] =
# Approach taken here is to simply collect messages, effectively, a circular
# buffer and only re-validate that they haven't already found themselves out
# of the network eventually via some exit message at block construction time
# at which point we use exit_epoch. It doesn't matter which of these message
# types has triggered that exit, as the validation on incoming messages will
# find it to either be IGNORE (if it's the same type of exit message) or, if
# it's a different type, REJECT. Neither is worth packaging into BeaconBlock
# messages we broadcast.
#
# Beyond that, no other criterion of the exit messages' validity changes from
# when they were created, so given that we validated them to start with, they
# otherwise remain as valid as when we received them. There's no need to thus
# re-validate them on their way out.
#
# This overall approach handles a scenario wherein we receive an exit message
# over gossip and put it in the pool; receive a block X, with that message in
# it, and select it as head; then orphan block X and build instead on X-1. If
# this occurs, only validating after the fact ensures that we still broadcast
# out those exit messages that were in orphaned block X by not having eagerly
# removed them, if we have the chance.
while true:
if subpool.len == 0 or result.lenu64 >= bound:
break
# Prefer recent messages
let exit_message = subpool.popLast()
if allIt(
getValidatorIndices(exit_message),
getStateField(pool.dag.headState, validators)[it].exit_epoch !=
FAR_FUTURE_EPOCH):
# A beacon block exit message already targeted all these validators
continue
result.add exit_message
subpool.clear()
doAssert result.lenu64 <= bound
func getAttesterSlashingsForBlock*(pool: var ExitPool):
seq[AttesterSlashing] =
## Retrieve attester slashings that may be added to a new block
getExitMessagesForBlock[AttesterSlashing](
pool.attester_slashings, pool, MAX_ATTESTER_SLASHINGS)
func getProposerSlashingsForBlock*(pool: var ExitPool):
seq[ProposerSlashing] =
## Retrieve proposer slashings that may be added to a new block
getExitMessagesForBlock[ProposerSlashing](
pool.proposer_slashings, pool, MAX_PROPOSER_SLASHINGS)
func getVoluntaryExitsForBlock*(pool: var ExitPool):
seq[SignedVoluntaryExit] =
## Retrieve voluntary exits that may be added to a new block
getExitMessagesForBlock[SignedVoluntaryExit](
pool.voluntary_exits, pool, MAX_VOLUNTARY_EXITS)